1. Field of the Invention
The present invention relates to a novel catalyst formulation. In particular, the formulation comprises a mixture of ceramic foam material and solid catalyst particles. The ceramic foam material is uniformly dispersed with the solid catalyst particles. The present invention also relates to a method of improving the catalyst life of a solid polymerization catalyst by uniformly blending reticulated ceramic foam material with the solid catalyst particles.
2. Description of Related Art
Typically, chemical reactor beds include discrete solid catalyst particles contained in one or more fixed beds. Many different techniques are available to increase the efficiency of the catalyst beds and to improve the catalyst life. One such method involves providing filtration of solids from organic based feedstreams to the chemical reactors, and providing flow distribution to the chemical reactors, by employing a reticulated ceramic material as a filter for the organic based feedstream prior to contact with the catalyst particles. See for example U.S. Pat. Nos. 6,258,600 and 6,291,603. The foregoing patents also note that the reticulated ceramic foam material can be coated to act as a catalyst in order to react with some of the impurities. The use of ceramic foams as a catalyst, generally as a base impregnated with an active material, is well known. See for example U.S. Pat. Nos. 5,510,056; 5,658,497 and 4,810,685.
The physical integrity of the catalyst particles also has a significant impact on the catalyst run length of a process. How quickly a catalyst breaks down and reduces void area determines when a process must be shut down in order to replace the catalyst.
Hydrocarbon polymerization units, such as motor fuel condensate units, are typically shut down every six to seven weeks due to high pressure drop across the reactor catalyst beds. Such catalysts, which can be made of, for example, diatomaceous earth impregnated with phosphoric acid, gradually break down and become structurally unstable as the run progresses. The rate of change of this instability can be controlled partially by operating conditions, such as, water content, injection rates into the feed, temperature and pressure. Regardless of how well the unit is operated, however, the final result is mechanical decay of the structural integrity of the catalyst. As the catalyst breaks down, the catalyst migrates into the openings that normally exist between the catalyst particles, thereby resulting in a loss of void area. This void area is critical in providing a space for the hydrocarbon feed that must flow across the catalyst in order for the reaction to proceed.
The shutdown of the unit and a change out of the catalyst due to the breakdown of the catalyst adds greatly to the economics of a reaction. Avoiding the expense associated with the need for frequent shutdowns and catalyst change would certainly be of great value to the industry. Improving the run length and the unit conversion by somehow avoiding the premature mechanical decay of the structural integrity of the catalyst would certainly result in a more economical and efficient chemical process.
Accordingly, it is an object of the present invention to provide a catalyst formulation which exhibits improved catalyst life and provides improved run length.
Another object of the present invention is to provide a chemical reactor containing the novel catalyst formulation of the present invention, for which unit conversion can be expected to increase as the chemical run progresses.
Still another object of the present invention is to provide a chemical process/unit for which the need for frequent shutdown and catalyst change is avoided.
These and other objects of the present invention will become apparent to the skilled artisan upon a reading of the following specification, and the claims appended thereto.